Phosphine borine compounds and their preparation



United States Patent PHOSPHINE BORINE COMPOUNDS AND p PREPARATION NoDrawing. Application June 17, 1957 Serial No. 666,207 1 i Claims. or.260-6065) This invention which is a continuation-in-part of ourcopending application, Serial No. 446,148, filed July 27, 1954, nowabandoned, relates in general to phosphine borine compositions which areuseful as intermediates in the preparation of phosphinoborines. Suchphosphine borines may be pyrolyzed whereby to remove hydrogen atoms fromboth the phosphorous and boron, thus yielding the desiredphosphinoborines.

The phosphine borines embraced by this invention have the'generalformula RR'HP:BH where the symbols R and R represent alkyl radicals ofless than 13 carbon atoms and lower alkenyl radicals and wherein atleast one of R and R represents a radical having at least two carbonatoms. Compounds of this type, when pyrolized and unusable polymer willbe obtained.

as set forth in our copending application Serial No.

666,205, filed even date herewith, form ring -(predomi nantly trimeric)phosphinoborines which are liquids and find particular utility whereheat-resistant hydraulic fluid I are required. 1

It is therefore an object of this invention to provide for thepreparation of phosphine borine intermediates which may be used toprepare phosphinoborines by pyrolysis. V

Generally, it has been found that when a phosphine and a borine, orsources thereof, are placed in a reaction vessel in contact with oneanother and the temperature conditions are properly adjusted, anaddition reaction occurs between these two ingredients whereby to form aphosphine borine addition product.

More particularly, it has been found that phosphine borines may beobtained from appropriatephosphines and borines by an addition reactionin the absence of moisture and in a non-oxidizing atmosphere. To aid ininsuring these conditions, the reaction vessel should be flushed withnitrogen or similar inert gas or be evacuated before the reactants areintroduced.

Under ordinary circumstances, the reaction is exothermic and tends tooccur vigorously. The vigor of the reaction may be at least partiallycontrolled by the use of suitable external cooling (Dry Ice and liquidnitrogen are effective coolants), by use of suitable diluents whichserve to-prevent the temperature of the reaction from becoming undulyhigh and which may act as the solvent medium for the reaction, or byusing both external cooling and a diluent.

The reactor should be formed of a material which will resist thecorrosive effects of the reaction and have suflicient strength towithstand temperatures and pressures that may obtain during thereaction. Where the process is carried out on a small scale, a heatresistant glass is suitable for use as a reactor.

The products of this invention are phosphine borine materials of thetype RR'HPzBH where R and R are .certain alkyl radicals of less than 13carbon atoms and lower alkenyl radicals. As set forth in ouraforementioned copending application, filed even date herewith, it isessential that the phosphine borines which are to be converted intophosphinoborines by the pyrolysis route contain only hydrogen atoms onthe boron. When a phosphine borine having one or morehydrocarbon'radicals on the boron atomis pyrolyzed, disproportionationoccurs, changing the phosphine borine initially presentto a phosphinetrialkyl borine, among other things, which cannot be converted to theuseful phosphinoborine. This occurs at temperatures below those requiredfor the loss of hydrogen from the phosphine boring reactant. Therefore aportion of the reactant is lost where a material having radicals otherthan merely hydrogen bonded to the boron is pyrolyzed. In addition, amixture of products is secured under such circumstances and control overthe course of the action is lost.

It is also essential that a single hydrogen, and a single hydrogen only,be bonded to the phosphorous if the phosphine borine is to be pyrolyzedto form a phosphinoborine. If no hydrogens are present initially, nonecan be lost and the phosphinoborine will not be formed. .But where morethan a single hydrogen is bonded to the phosphorous, and such materialis pyrolyzed, these extra hydrogens will be driven off and a highlycross-linked Example I Methylethylphosphine, CH3(C2H5)PH\ in the amountof 6.84 g. was placed in 300 ml. round bottom flask which had beenpreviously evacuated and externally' cooled to -78- C. by means of solidcarbon dioxide. Diborane, B H in the amount of 1.24 g. was passed intothe flask. As the addition of the diborane continued, thetemperatureincrease d somewhat and the final temperature reached 0 C. Aquantitative yield of'methylethylphosphine borine, CH (C H )HP:BHmelting below 78 C. was secured. The compound is a colorless liquid.

I Example II p v ,A 300 ml. flask was flushed with nitrogen and fittedwith a distilling head and an addition funnel in which nitrogen was alsomaintained. 200 ml. diethyl ether were .added to the flask followed by21.32 g. diethylphosphine, (C H PI-I, through the addition funnel. Theflask had been cooled to 20 C. by external applica tion thereto of DryIce preceding the addition of the aforementioned materials. Thereafter,4.81 g. diborane were passed into the flask through the addition funnel.As the diborane was added, the'temperature was allowed to warm slightlyso that 0 C. was reached at the conclusion of the diborane addition. Ayield of the diethylphosph'ine borine was secured following the removalof the solvent by distillation at a reduced pressure. The reactionproduct has the formula (C H HP:BH

Example I II Example IV Dodecylmethylphosphine, C H (CH )PH in theamount of 12.96 g. was placed in a 300 ml. round bottom flask which hadpreviously been evacuated. 0.83 g. diborane was thereafter passed into aflask while the latter was maintained at 78 C. by means of solid carboninvenwas thus obtained.

1 Example V A 250 ml. round bottom flask was fitted with an ex tendedneck consisting of a water condenser, a gas inlet tube extending to thebottom of the flask and a gas outlet tube. Into the reaction vessel wasdistilled 29.4 g. of methyl-i-propylphosphine and 25.0 g. ofmethylethylphosphine. The reaction flask was immersed in a Dry Iceslurry at 78 C. and a mixture of diborane and nitrogen gas bubbled intothe mixed phosphines until diborane appeared in the excess gas, whichpassed through a mercury bubbler and into a Bunsen burner. The apparatuswas swept with nitrogen to remove excess diborane yielding a mixture ofaddition compounds, i.e., methylethylphosphine borine andmethyl-i-propylphosphine borine.

The stoichiometry for and additional information regarding further runswherein a phosphine may be reacted with diborane to produce a phosphineborine addition product are set forth in the table below.

invention is the provision that three hydrogens must be bonded to theboron and a single hydrogen to the phosphorous. Where materials otherthan hydrogen are bonded to the boron, the aforementioneddisproportionation occurs at temperatures below those required for theloss of hydrogen from both boron and phosphorous to form aphosphinoborine. Where more than a single hydrogen is bonded to thephosphorous, the compound will lose more than a single hydrogen fromsuch phosphorous on pyrolysis with the result that a highly cross-linkedglassy material will be secured.

Obviously many modifications and variations of the invention ashereinbefore set forth may be made without departing from the spirit andscope thereof, and therefore only such limitations should be imposed asare indicated in the appended claims.

We claim:

1. A phosphine borine having the formula RR'HP:BH where R and R areselected from the group consisting of alkyl radicals having less than 13carbon atoms and lower alkenyl radicals and where at least one of R andR includes at least two carbon atoms.

2. Methylethylphosphine borine.

3. Methyl-i-propylphosphine borine.

4. Diethylphosphine borine.

5. Di-i-propylphosphine borine.

6. Hexylrnethylphosphine borine.

Approx. Example Phosphine Grams Grams Reax. Phosphlne Bortne Product N0- Dlborane Temp.,

11-C|Hs(CHa)PH- 1. 25 0. 162 78 11-O4H9(OH3)HP2BH:.

11. 33 1. 52 0 (11-05111!) 2H]? EH3.

9. 23 0. 97 -70 Il-CQH13(GH3) HP EH. 9. 92 1. 38 70 C7HIB(C2H5)HP I EH3.8 (CH3)PH 1. 04 0. 091 60 CsHrKCHQHP 2 EH3. CH:=CHCH2(G H5) H 1. 1O 0.152 0 CHa= CHOH2 O2H5 HP 2 BH:.

(CQ IQZPH 1- 616 0. 115 --78 (0511 92111 H3. BHVDZPH 21- 6 2. 77 2O(CaHnhHPZBHa. CH3CH=OHCH2(C2H5)HP-- 12. 76 1. 52 -3OCH3CH=CHCH2(G2H5)HP2BH (l -O:H7)2PH 0. 675 0. 126 78 (Tl-C3311) :HP EH3.

As can be seen from the foregoing, it is possible to make a wide varietyof phosphine borines by following the teachings of this invention. Allof the materials described herein are included within the scope of thegeneral formula RR'HPzBH where R and R are alkyl radicals of less than13 carbon atoms and lower alkenyl radicals and where at least one of Ror R' contains at least two carbons. Thus the most elementary compoundfalling within the scope of this invention is that set forth in ExampleI, CH (C H )HP:BH This material may be pyrolyzed as set forth in ourcopending application, Serial No. 446,147, filed July 27, 1954, and inapplication Serial No. 666,205, filed June 17, 1957, to yieldphosphinoborines which are ring polymers and which are liquids atordinary temperaturestherefore finding utility as hydraulic fluids anddielectrics under conditions where extremely stable materials arenecessitated.

A divisional application of the aforementioned application Serial No.446,147, which is identified as Serial No. 754,914, filed August 14,1958, describes and claims compounds of the type into which thephosphine borines of this invention may be converted.

As set out earlier, another essential feature of this 7. A phosphineborine having the formula wherein R is an alkyl group having at least 2and less than 13 carbon atoms.

8. A phosphine borine having the formula R(C H )HP:BH

wherein R is an alkyl group having less than 13 carbon atoms.

9. A phosphine borine having the formula wherein R is an alkyl grouphaving less than 13 carbon atoms.

10. Dodecylmethylphosphine borine.

References Cited in the file of this patent UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent No. 2,916,518 December 8 1959 I AntonBa Burg et al9 It is hereby certified that error appears in the abovenumbered patent requiring correction and that the said Letters Patentshould read as corrected below,

In the grant lines 2 and 3 for "assignors to The University of SouthernCalifornia, a corporation of (Iialiiornia read assignors 10y mesneassignments to American Potash & Chemical Corporation a corporation ofDelaware -gv line l2 for "The University of Southern California itssuccessors read American Potash 8: Chemical Corporation its successorsgin the heading to the printed speciificatiom lines 5 and 6 for"assignors to The University of Southern California a corpora tion ofCalifornia" read assignora by mesne assignments to American Potash 8:Chemical Corporation a corporation of Delaware Signed and sealed this5th. day of July 19600 (SEAL) Atfiest:

KARL Ha AXLINE RUBERT c. WATSON Attesting Officer Comnissioner ofPatents

1. A PHOSPHINE BORING HAVING THE FORMULA RR''HP-HP:BH3 WHERE R AND R ARESELECTED FROM THE GROUP CONSISTING OF ALKYL RADICALS HAVING LESS THAN 13CARBON ATOMS AND LOWER ALKENYL RADICALS AND WHERE AT LEAST ONE OF R ANDR'' INCLUDES AT LEAST TWO CARBON ATOMS.